In some cases it may be best to remove the incrustations by the aid of 

 oxahc acid. This should be done carefully by brushing on the acid with a 

 camel's hair brush and then the surface washed with water. Dipping in 

 the oxalic acid may be necessary and in this case the whole shell should 

 be immersed for a few moments and then washed in cold water to remove 

 the acid, which acts very quickly on the limy shells. 



The operculum of the larger shells should be preserved by cutting it 

 away from the muscular foot. All traces of flesh must be removed from the 

 under side of the operculum. It should be dried and placed on a bit of 

 cotton in the aperture of the shell from which the operculum originally 

 came. This is important. All large shells should be carefully dried by 

 natural, not artificial, heat. Do not place snail shells on a hot stove or 

 heater or in the oven. Room temperature is sufficient. Campeloma and 

 Viviparus may be rubbed with a cloth slightly moistened with vaseline to 

 retain the original luster of the shell. All excess vaseline should be removed 

 or the shell will feel greasy. This treatment also helps to keep the epidermis 

 from cracking and peeling. 



The little limpet snails, Ferrissia, should have the animal carefully 

 removed from the shell with the fine point of a dissecting needle. These 

 little limpets are usually coated with algae or lime and may be cleaned by 

 being allowed to float, upside down, in the surface of a small quantity of 

 oxalic acid, after which they may be washed and carefully wiped with a 

 camel's hair brush. The shell may be easily cleaned if held, bottom 

 upward, on the tip of the index finger. 



For more extensive information on collecting and preserving mollusks 

 the reader is referred to the following paper in which there is, also, a 

 bibliography of other papers relating to this subject. 



Preparing collections of the Mdllusca for exhibition and study. By FRANK C. 

 BAKER. Published in the Transactions of the American Microscopical Society, Volume 

 XL, No. 1, pages 31 to 46, 1 92 1. 



TRAPPING FRESHWATER SNAILS 



By Leonard N. Allison 

 Reprinted from Science, Vol. 95, No. 2457, pp. 131-132, 1942 



An efficient method of collecting the snail, Campeloma sp. in streams 

 was found during a study of the life history of the trematode worm Cer- 

 cariaeum constantiae Mueller. Since Campeloma habitually burrows, the 

 collection of these snails in quantity by screening consumes much time and 

 is hard work. While collecting these snails in the Huron River near Ann 

 Arbor, Michigan, I noted that they were frequently found in considerable 

 numbers around dead and decaying organic matter. To determine the time 

 required to accumulate a quantity of snails, a dead fish weighing a pound 

 was placed in the mud where earlier collections had been made. Ten days 

 later, an area of approximately one foot square and 6 inches deep around 

 the fish yielded 78 Campeloma, a number far exceeding those taken in 

 similar, but unbaited situations. 



(58) 



